Exporing differents abiotic data sources
Bathymetry
Mean_bathy.tif from Beauchesne and bathymetry.tif from GEBCO
The scale of bathymetry.tif seems to be finer than bathy_mean.tif:
This is the differences between both datasets. Most of this difference must come from the different scale for both datasets.
Should we use other variables derived from bathymetry? (https://www.frontiersin.org/articles/10.3389/fmars.2021.652540/full)
slope
TPI (Topographic Position Index): difference between the value of a cell and the mean value of its 8 surrounding cells
TRI (Terrain Ruggedness Index): mean of the absolute differences between the value of a cell and the value of its 8 surrounding cells
roughness: difference between the maximum and the minimum value of a cell and its 8 surrounding cells
TPI seems quite uniform over the entire area of study, so maybe it’s not that relevant to use it. Slope, TRI and roughness seems strongly correlated. Let’s see:
bathymetry slope TRI roughness
bathymetry 1.00000000 0.02550875 0.01108015 0.01528311
slope 0.02550875 1.00000000 0.90531682 0.94775283
TRI 0.01108015 0.90531682 1.00000000 0.94613523
roughness 0.01528311 0.94775283 0.94613523 1.00000000
Since everything is strongly correlated, we should only use one of these three variables. Let’s use slope since it’s more intuitive to picture.
To summarize, for bathymetry and derivatives, we should use:
the bathymetry from GEBCO since the scale is finer and
the slope, since it’s strongly correlated with TRI and roughness and it’s more intuitive to picture.
Oxygen
oxygen_[2011-2020].tif from DFO
sat.tif from Beauchesne (I presume this is bottom dissolved oxygen from Blais 2019?)
bio-oracle dissolved oxygen
EGSL data from DFO seems incomplete (oxygen_[2011-2020].tif):
Oxygen saturation? from Blais 2019?
Dissolved oxygen is also available from bio-oracle:
Primary productivity
Since we’re modelling sea pens, should we focus on bottom primary production? If so, then we have two datasets for now:
present_benthic_mean_depth_primary_productivity_mean.tif from Beauchesne
bottom_primary_productivity.tif from bio-oracle
Is it relevant ot use if most of primary productivity seems to be near the coast and that sea pens are mostly deep in the water?
Salinity
There is two datasets of bottom salinity:
salinity_[2011-2020].tif from DFO
salmoymoy.tif from Beauchesne, from Dutil 2011?
Salinity from Beauchesne seems very “uniform” compared to DFO data. But there is a part missing for salinity_[2011-2020].tif northeast of the area of study.
Let’s see what bio-oracle salinity looks like (V2.2)
Temperature
We have two datasets:
temperature_[2011-2020].tif from DFO
sbt.tif from Beauchesne (I assume this is bottom temperature from Galbraith 2018?)
Again, there is a portion northeast of the area of study without any data for temperature_[2011-2020].tif.
The difference between both datasets seem minimal
Current velocity
Should we use current velocity since it can relate to anchoring ability of the sea pens (https://www.frontiersin.org/articles/10.3389/fmars.2021.652540/full).
Here are the min, mean and max current velocity at mean depth from bio-oracle.
I’m showing V2.1 because the minimum current velocity values in V2.2 are greater than mean current velocity, which seems odd.